Tag Archives: global warming

Dying Coral Reefs

by Krista Bergesen

With the global climate changes going on right now, it may not be surprising to know that the aquatic life is also being affected. Displayed in every vacation resorts catalog and ocean documentary, coral reefs have formed an integral part of the planet’s oceans, providing a food supply, habitat, and protection for many other sea creatures.

Sometimes, it is easy to imagine coral as the dead, funny shaped rock that can be seen when you go scuba diving. Surprising as it may be, coral are actually living animals that eat, breathe, and reproduce.

Often mistaken for plants, coral use tentacles to sting and capture their prey of small fish and small animals. Hard to imagine, right?

It may be interesting to note that coral also located all across global waters. In colder northern waters, the coral don’t generally settle down into the picturesque colonies of the equatorial waters, but are still there floating aimlessly throughout the water. Large colonies are formed in the presence of algae, where the coral can feed off of the algae’s products of photosynthesis. At the same time, the coral produce CO2 to feed the algae. Not having to capture prey anymore because of this mutualistic relationship, the coral then produce the calcium carbonate exoskeletons that people usually identify with the species.

Coral reefs may look rock hard and impermeable, but they are surprisingly fragile.

Myriads of creatures graze on and make their homes in the coral. And the coral are always dying and re-growing their structures because of the constant attack they are under. A very delicate balance of destruction and growth has been maintained for millions of years between the coral and the rest of the ocean. It figures that humans would mess it up.

Instead of carrying fresh, clean water to the oceans, rivers now carry agricultural waste. Nitrates, phosphates, sewage, etc. now pollute the water. Recent evidence has found that coral now faces disease susceptibility from the sediment accumulation and increased exposure to land-based pathogens.

It doesn’t stop there, global warming has, not surprisingly, caused problems as well. As coral and algae colonies evolved together in a very narrow temperature range, the algae have begun to produce poisonous oxygen compounds called “superoxides” because of the higher oceanic temperatures. The coral will consequently expel the algae only to starve and turn a deathly white, giving the process the name of “bleaching.”

Coral reefs only form a small portion of the vast oceans, but their presence showcases the biodiversity and intricacy of the ocean’s natural systems. Widespread coral bleaching as well as pollution will change the face of the oceans as we know it through extinction. And this type of change cannot be undone.

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Filed under Biology, Ecology